Problem: Michael is 5 times as old as Jessica and is also 24 years older than Jessica. How old is Jessica?
Solution: We can use the given information to write down two equations that describe the ages of Michael and Jessica. Let Michael's current age be $m$ and Jessica's current age be $j$ $m = 5j$ $m = j + 24$ Now we have two independent equations, and we can solve for our two unknowns. Since we are looking for $j$ , and both of our equations have $m$ alone on one side, this is a convenient time to use elimination. Subtracting the second equation from the first equation, we get: $0 =$ $5j$ $-$ $ (j + 24)$ which combines the information about $j$ from both of our original equations. Solving for $j$ , we get: $4 j = 24$ $j = 6$.